He added that the smell caused his asthma to flare up, saying, "I had a tightness in my throat."

The YMCA said it took action immediately after the odor was reported.

"Earlier this afternoon, a lifeguard at our Downtown Durham YMCA reported a strong chemical odor near the pool pump room," the YMCA said in a statement. "YMCA staff immediately contacted EMS. They, in turn contacted the Durham Fire Department who determined that this was a hazmat situation."

The statement continued: "Today, approximately 100 campers from our Club Boulevard Elementary Club location swam in the Downtown Durham YMCA pool. As part of their daily routine, they were taken back to their camp at Club Boulevard Elementary School. At about 3:00 p.m., some children began complaining about nausea and breathing issues. Our camp staff immediately contacted EMS and began notifying parents."

The pool has been closed, Durham County Emergency Management and the YMCA said. An investigation into the incident is underway.